In the industries (such as the electricity, the petrochemistry, the transportation, the metallurgy, the coal and so on), it is a common method of equipment management to lock the door of the equipment and the manual operating mechanism using the lockset. Using a key to operate the lockset is a common method of equipment management, and security arrangement which is essential to avoid accidental risk. Nowadays, the lockset for locking is the ordinary lockset available in the market primarily. Such kind of lockset usually encompasses the lock core with the structure of “bullet-spring” or “bland”. Such structure has significant defects if applied in industries. The defects are mainly reflected in terms of reliability. (a) Due to the incomplete rain-proof structure, the parts of the lock core are easily prone to rust. Such phenomenon is especially observed in the oceanic climate, acid rain climate, or the environment which may induce an electrochemical reaction. (b) Since the unlocking hole does not have the dustproof structure, under the condition of a sandstorm, the dust can enter the lock core through the unlocking hole easily, which makes it impossible to open the lock. With respect to this problem, people tried to develop new lockset structure to deal with the above defects. For example, the intention patent whose number is ZL201410107543.3 filed by the present applicant previously and which is titled as a lock core structure with a magnetic encoding free monad style. As shown in FIG. 1, the lock core structure includes lock core casing 101, lock knob 104 which is rotatably provided in the internal cavity of lock core casing 101, lock core front end cover 102 and lock core rear end cover 103 that are located at both ends of lock core casing 101. The internal wall of the lock core casing 101 is provided with at least one monad longitudinal moving groove and at least one monad horizontal rotating groove. The end that corresponds to lock core front end cover 102 along the axis line on the lock knob 104 is provided with the unlocking hole of the magnetic encoding key. The external wall of the lock knob 104 is provided with a plurality of monad longitudinal slide-ways 112. At least one of the plurality of monad longitudinal slide-ways 112 is provided with a free monad. The free monad is big monad 107 and small monad 108. The monad longitudinal slide-ways 112 and the monad longitudinal moving groove corresponds to each other and form a monad moving cavity. When the lock core is in the locking position, at least one big monad 107 is located at a position where the monad moving cavity and the monad horizontal rotating groove stagger with each other, or at least one small monad 108 is partially located in monad longitudinal slide-ways 112. When the lock core is in the unlocking position, the big monad 107 is located at a position where the monad moving cavity and the monad horizontal rotating groove intersect, and small monad 108 is located entirely in monad longitudinal slide-ways 112. The magnetic encoding lock core designed with this structure has the advantages of good security, high reliability, easy digital management, simple structure and process of manufacture, and low cost of production. Conditions of being applied in industries are satisfied. The magnetic encoding key in the prior art cannot open the above lock core structure, which puts forward a higher requirement for the core part of the magnetic encoding key —the magnetic unlocking device.